Mac Complaint

I have to admit that I have a Mac complaint, something I almost never have. I can't satisfy myself with a browser that fills all my needs. On any other platform (Windows or Linux) Firefox is ne plus ultra, but I find the OS X version (FF 1.5 on OS X 10.4.5) to annoy me sometimes. The biggest problem I have is that seemingly at random it will be incredibly slow to enter text in a form (lagging many seconds behind my typing). It also scrolls really slowly and must have some cache checking problem because scrolling also cause the hard drive to start clicking.

I had these problems before and I remember web searching to find something (maybe having to do with OS X's font cache?) to fix it, but now it's back and I've been searching and pulling my hair out to no avail. Anybody else have this issue? Anybody have a clue what the story is?

Safari is a reasonable alternative but lacks a few things that I've become accustomed to in FF (AdBlock, the ability to have wikipedia and IMDB in my drop down search box) and doesn't deal with some sites adequately (for instance it can't handle the fancy rendering on the Typepad UI that I'm currently using).

Mac fiends who read this bløg, do you have any advice?